CZ20031785A3 - Method for real-time adjustment of a planisher for planishing metal strips, plates and sheets and a planishing device comprising such planisher - Google Patents

Abstract

A method for real-time adjustment of a planisher for planishing metal strip. After a planished strip has been cut into a plate, the method includes measuring the plate at the output of the planisher outside a support zone, correcting the measurement so as to eliminate the influence due to self-weight of the plate, and correcting, as the case may be, the clamping of rollers located at the planer output so as to obtain a plate with a controlled curve.

Description

-1A real-time straightening method for straightening metal strips, plates or sheets, and straightening equipment containing straightening machine

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a method of regulating a straightener for real-time straightening of metal strips, plates or sheets, for straightening metal strips from coils, such as steel strips, or directly to plates or sheets. The invention further relates to a straightening device comprising a straightener for straightening metal strips, plates or sheets.

The invention therefore relates both to the straightening of metal strips to be cut at the outlet of the straightener so as to obtain plates or sheets of a specified length L, and to the straightening of the plates or sheets.

BACKGROUND OF THE INVENTION

The metal strip or plate undergoes various manufacturing operations, such as hot rolling and cold rolling, intended to impart uniform dimensional properties over its entire length. Thus, the rolled metal strip has theoretically the same thickness and width at each point. However, the rolling operation is not sufficient to obtain a defect-free belt. In fact, it may exhibit flatness defects such as undulations at the edge or in the middle, and deflection (i.e., curvature) along the length or width of the strip.

These flatness defects are corrected by straightening the strip in the straightener. Such a straightener is formed by two stacked cartridges, each containing a plurality of driven rollers, offset to each other and positioned alternately above and below the track

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-7.pass. In the case of a metal strip in a coil, it unfolds before, and is generally straightened in a straightener before the strip is straightened. In order to provide products meeting the criteria required by the manufacturers, flattened strips are not rewound, as winding damages flatness. Thus, they are sheared at the exit of the straightener so that boards, boards or clippings are obtained, either with guillotine shears or trimming shears, orbital or flying. The straightened sheets or sheets are then conveyed to a stacker where they are stacked and await shipping.

Straightening is effected by passing the strip or plate between the offset rollers of the straightener, in which the inlet grip is regulated, i.e. the distance of the rollers at the inlet side of the straightener, and the outlet grip, i.e. the distance of the rollers at the outlet of the straightener. At the inlet of the straightener, residual belt tensions are homogenized to eliminate flatness defects such as ripple and width curvature. At the output of the straightener a curvature is applied along the length of the strip. For the sake of simplicity, in the following text, whenever a curvature along a length is to be mentioned, only the curvature is briefly referred to.

The clamping parameters at the inlet and outlet of the straightener are adjusted each time the coil and plate (or sheet) are changed to accommodate not only the dimensional properties and types of belt or plate defects, but also depending on the deflection depending on the shape to be supplied to the plate (or chalkboard) for straightening.

Depending on the intended use of these flattened boards (or boards), or depending on the type of September-3

• The equipment these processors have will be supplied with zero curvature (perfectly planar plate), positive curvature or negative curvature.

First, the clamping of the rollers of the straightener at the inlet is controlled by methods known per se, and the clamping of the rollers at the outlet is controlled.

A known means for regulating the straighteners rollers at the outlet is to control the residual curvature of the plate (or sheet) after straightening. For this purpose, the plate is lifted by means of a hoist to be suspended by one or two support points, whereupon the operator measures the curvature of the plate by detecting the deflection in the center of the plate by means of a ruler. The operator can then adjust the clamping control of the rollers at the outlet to correct the curvature of the plate and adapt it to the requirements of industrial use. This measurement is renewed as many times as necessary during product change (in the form of a coil, plate or board).

This procedure presents various disadvantages. The first disadvantage is that measuring the curvature of the plate when changing the product and adjusting the gripping of the rollers at the exit by the operator requires stopping the straightening line during this process, resulting in a loss of production. Because some straightening lines are compact, it is not always possible to incorporate plate lifting devices. In this case, the curvature measurement of the plate is made off-line with an even longer stopping time. A further disadvantage is that lifting the plate can entail risks to the operator, especially in the case of large-sized plates (longer than 2 m).

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In addition, the problem is that although the dimensional properties of the strip of a single coil are constant over its entire length, this does not apply to the mechanical properties. However, deviations in the mechanical properties of one strip have a negative impact on managing the final curvature of the plates after straightening the strip. Since the grip of the rollers at the outlet has been adjusted for a given mechanical property of the strip, this grip will no longer be adapted during straightening if the mechanical properties of the strip deviate significantly.

Managing the residual curvature of the plate is an important measurement process, as the tolerances required by industry for the curvature of the plate are increasingly narrower. As an example, it is currently noted that the tolerances regarding the curvature of laser cutting plates and for certain automotive applications as fasteners are often less than ± 3 mm / m. It is an object of the present invention to overcome these disadvantages of the prior art method.

SUMMARY OF THE INVENTION

The present invention provides a method of regulating a straightener for real-time straightening of metal strips, plates or sheets, characterized in that:

after straightening the strip, the strip is cut to obtain a straight board or straightened board, the curvature of the straight board exiting from the straightened board or straightening board is measured, at the straightener outlet outside the support area, the measured value is corrected to eliminate the net weight effect and, if necessary, the clamping of the rollers mounted at the straightener outlet is corrected to obtain a flattened plate with controlled curvature.

According to a further feature of the invention, the measurement of the residual curvature of the flattened plate is performed by measuring the curvature of the flattened plate at the straightener outlet outside said support area, the measurement being carried out by means of at least three proximity sensors.

According to another feature of the invention, the measurement of the residual curvature of the flattened plate is derived from the measured curvature and the actual curvature of the flattened plate.

The invention further provides a straightening device comprising a straightening machine for straightening metal strips, plates or sheets, the device characterized in that it comprises means for cutting, after straightening, a strip for straightened plates or straightened plates, measuring means for measuring the residual curvature of straightened plates or straightened plates. and a means for varying the grip of the rollers lying on the straightener outlet depending on the data provided by the measuring means for measuring said residual curvature.

According to a further feature of the device according to the invention, said means for measuring the residual curvature comprise at least three distance sensors, such as optical distance sensors or distance sensors based on the Foucault current principle.

According to a further feature of the invention, the device comprises automatic means for regulating the clamping of the output rollers in dependence on the distance measurement data by the sensors.

According to a further feature of the device according to the invention, the measurement of the curvature of the flattened plate is performed at the level of said flattened plate outside the support area.

As is apparent from the foregoing, the invention consists in making a real-time measurement of the residual curvature of a slab or strip cut into slabs at the exit of the straightener, and controlling the clamping of the rollers as a function of the results of the measurement.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in more detail below with reference to the accompanying drawings, in which: FIG. 1 shows a schematic cross-section of a straightener and FIG. 2 shows the dependence of the residual curvature value on the gripping of rollers at the outlet of the straightener.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, a straightener 1 is shown schematically with two cassettes 2 supported thereon, carrying the driven rollers 4, offset with respect to one another, between which a metal strip 5, a plate or a sheet metal sheet is moved. The apparatus comprises shearing means 6 disposed at the outlet of the straightener, a transport table 7, and means (not shown) for conveying a strip cut into plates. In the case of straightening strips, the device comprises cutting means 6 disposed at the outlet of the straightener. It will be understood that the shearing means 6 are unnecessary when the shear means 6 are unnecessary.

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straighten plates or sheets. However, they can be present on the equipment and will not be put into operation in this case. In the figure, a plate 8 or sheet (derived from shearing the strip after straightening or from a flat board or sheet) is shown, one part of which is supported on table 2 and the other part extends beyond table 7. Distance sensors (not shown) The plates 8 not supported by the table 7 are connected to the clamping control system 11 of the rollers 4a and 4b located at the outlet of the straightener which itself is connected to the clamping actuator 12 at the outlet (the rollers 4a and 4b).

The metal strip 5 or plate is straightened in the straightener 1 by passing between the rollers 4. At the outlet of the straightener, the strip 5 is sheared by shearing means 6 formed by guillotine shears or rotary shears, tracing or flying, so as to obtain plates 8 A portion of the flattened plate 8 rests on the conveyor table 7, while the length L 'predetermined by the detection cell 10 extends beyond the table 7 and therefore lies outside the support area.

At least three sensors 9 mounted on a reference stand, not shown, located either above or below the area corresponding to the length L 'of the plate 8, measure the distance separating said portion of the plate length L' so as to determine its curvature C. The measurements made by the sensors 9 are preferably non-contact measurements distance to prevent distortion of the measurement of the curvature of a portion of the plate 8 of length L '. Contactless distance sensors 9 such as Foucault current sensors or optical sensors are therefore used.

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In order to determine the residual curvature C _{r of the} plate 8 from the measured curvature C, it is appropriate to take into account the curvature C _{p of the} plate 8 resulting from its own weight. Knowing the parameters L 'of the plate 8 extending beyond the table 7, determined by the position detection cell 10, the plate thickness 8, and the distance of the sensors 9 from the table 7, allow to calculate the curvature Cp of the plate 8 resulting from its own weight. By subtracting this curvature value C from the measured curvature value C, the residual curvature C _{r of the} plate 8 is thus easily obtained.

Knowing the residual curvature C _{r of the} plate 8, a transmission function is calculated which then allows to adjust the grip at the outlet (rollers 4a and 4b) of the straightener 1 so that the curvature of the subsequent plate 8 is adapted to the requirements of the intended industrial application.

The industrially desired curvature of the plate 8 may be zero (plate perfectly straight), positive (plate curvature upward) or negative (plate curvature downward). In order to obtain plates having one of these profiles, it is appropriate to either loosen or tighten the clamping of the rollers 4a relative to the rollers 4b at the outlet of the straightener 1.

This process can be performed by the operator, who collects the various previously performed measurements, calculates, using these measurements, the transmission function to derive the grip parameters at the outlet of the rollers 4a and 4b for introduction into the control system 11 according to the curvature to be supplied to the board. This process can also be performed automatically by a computer.

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4 44 · · 4 4 ··· · 4 4 4 4

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Once the gripping parameters of the rollers 4a and 4b have been determined, the actuator 12 acts directly on the gripping of the rollers 4a and 4b at the output of the straightener 1, i.e., their mutual distance.

The method according to the invention thus allows the curvature of each of the plates 8 to be controlled in real time. When the characteristic mechanical properties of the plate 8 change from one coil, the curvature control of the plate 8 allows real-time clamping parameters to be applied immediately. the clamping at the outlet (rollers 4a and 4b) to obtain plates 8 whose curvature is constant and whose residual curvature remains within the limits established by industrial use.

In addition to the above advantage, the method of the invention eliminates the plate lifting and curvature measurements by the operator, and has the following additional advantages over the prior art:

- improving safety conditions,

- abolition of plate handling times, thus enabling the overall line productivity to be increased,

- speed of roll-off corrections when using a self-timer,

- due to the easy-to-check curvature of the slab, there is no limitation to slabs of less than 3 m in length at 3 mm thickness, as in the prior art method,

- space gain, since the device according to the invention is compatible with compact devices and therefore requires less space than is required for lifting the plate,

- systematic check of the curvature of all plates (archiving) ···························

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values).

Fig. 2 shows the variation of the residual curvature (expressed in mm / m) as a function of the clamping of the rollers at the straightener outlet (expressed in mm).

The material under consideration is a steel strip with a thickness of 6 mm, a width of 1500 mm and a yield strength of 350 MPa. The initial plasticization rate of the web is 60%. The maximum plasticization rate considered for this example is 80%. The degree of plasticization granted depends on the straightening strategy used and the initial flatness of the strip prior to straightening. The amplitude of the curvature deflection is directly related to this parameter.

The following examples serve to illustrate the use of the method.

In Example 1, the non-contact distance sensors measure the residual curvature of the plate obtained after straightening and shearing a steel strip of +7 mm / m. In order for this plate to be zero (perfectly planar plate), the control system (a) must correct the clamping of the output rollers of the plane by a correction of 0.15 mm so that the clamping reaches 0.32 mm.

In Example 2, the non-contact distance sensors measure the residual curvature of the plate obtained after straightening and shearing a steel strip of -7 mm / m. In order for the plate to be curved to zero (perfectly planar plate), the control system (a ') needs to correct the clamping of the output rollers of the plane of the correction by 0.2 mm so that the clamping reaches 0.32 mm.

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Claims (9)

·· ·· PATENTOVÉ Claims A method of regulating a straightener for real-time straightening of metal strips, plates or sheets, characterized in that after straightening the strip (5) the strip is cut to obtain a straight plate (8) or a straight sheet, the curvature of the straight sheet (8) is measured. ) of the cut strip (5) or of the straightening machine (1) outside the support area, the measured value is corrected to eliminate the effect of the weight of the flattened plate (8) and, if necessary, the clamping of the rollers (4a, 4b) straighteners (1) to obtain a flattened plate with controlled curvature. extending from the straightening plate (5) at the outlet Method according to claim 1, characterized in that the measurement of the residual curvature of the flattened plate (8) is carried out by measuring the curvature of the flattened plate (8) at the outlet of the straightener (1) outside said support area. distance (9). Method according to claim 1 or 2, characterized in that the measurement of the residual curvature of the flattened plate (8) is derived from the measured curvature and the actual curvature of the flattened plate (8). Straightening device, comprising a straightener for straightening metal strips, plates or sheets, characterized in that it comprises means for shearing, after straightening, a strip (5) for flattened plates (8) or flattened sheets, measuring means for measuring the residual curvature of flattened plates (8) or flattened sheets emerging from straightening of the cut strip (5) or flattening of plate (5) or sheet, at the output of the straightener (1), and means for varying the grip of the rollers (4a, 4b) lying at the outlet of the straightener (1) depending on the data provided by the measuring means for measuring said residual curvature. Straightening device according to claim 4, characterized in that said residual curvature measuring means comprise at least three distance sensors (9). Straightening device according to claim 4 or 5, characterized in that said residual curvature measuring means comprise at least three optical distance sensors (9). Straightening device according to claim 4 or 5, characterized in that said means for measuring the residual curvature comprise at least three distance sensors (9) based on Foucault currents. Straightening device according to any one of claims 4 to 7, characterized in that it comprises automatic means for controlling the clamping of the output rollers (4a, 4b) in dependence on the distance measurement data by the sensors (9). A straightening device according to any one of claims 4 to 4. -13ι «9 9 «« 9 »» 9 9 9 9> * · 98 8, characterized in that the measurement of the curvature of the flattened plate (8) is carried out at the level of said flattened plate (8) outside the support area. • WDr. Petr Kabriský lawyer f 5 i 4 Oí V '.''FROM: MY Š' · '· í \ 1> AB · ^; / 1 (her) F + ah Czech .-. . - ¹ - ,; j.hova 2 JÍii \ 3